It came out fairy well, the colors indicating the serious mood of the picture. I think though that the ice cannon might be seeming too different from the rest. Another thing (sorry, trying to be professional here), the nose is too large for the face and his lips are slightly too full. If you could turn down on the ice cannon's colors and dimensions that can be easily fixed, same with the other minor errors I've listed. Remember that I am not a professional and could not have even minimally accomplished what you have. (I'm just a die-hard Gray fan)
I'm in love with this image. I'm a huge perfectionist, and find flaws in almost everything done. The bicep shown, his left, looks a bit too wide for the muscles given on the rest of his body / arm. The pants and the shading are done well, but the ice cannon bothers me a little. I like the frozen effect you added, but it needs more of a solid appearance, and not so transparent. More shading rather than lighting can easily fix that. The facial features are only slightly off. Gray lacks the protruding nose you gave him, and his bottom lip seems fuller than it should be. The hair is done greatly, though, and I have no complaints / nit-picks about it. The shading under the eye seems a bit too colored compared to the shading and coloration of the rest of the body. If you were aiming for a faint blush, try moving it inward a little and make it reach for the nose, but don't let it cover the nose.
The "minor" details done on the cross necklace really make it stand out, and I love it. Very few people can manage a good adornment like that. The icey mist given off from the cannon really helps make the picture, and the background is lovely. Not too much as to take away from Gray, but not too little as to make it bland. You found a great medium, and I applaud you for it.
I'm a die-hard Fairy Tail fan, and I rarely find any pictures like this that truly interest me, but yours does to a great extent. Over all this picture is great, and the silent statement it makes fits Gray's personality. Amazing job. c:
I have to agree with that the nose is a little too big looking, however, I do love how the ice looks. I am not a big fan of the veins though as generally veins do not show like that unless someone is really flexing or on steroids and I would prefer to believe that my Gray is not on those :-P Keep up the amazing work though!!